Influence of Electroless Coating on Bottom Ash Reinforcement in Aluminum Matrix Composites: A Study of Microstructure and Mechanical Properties Sefrian Rizki Bintoro (a), Eko Surojo (a), Nurul Muhayat (a), Triyono (a*)
a) Department of Mechanical Engineering, Universitas Sebelas Maret
Jl. Ir. Sutami No.36, Jebres, Kec. Jebres, Kota Surakarta, Jawa Tengah 57126, Indonesia
*triyono74[at]staff.uns.ac.id
Abstract
Aluminum Matrix Composites (AMC) are widely applied in aerospace, transportation, and mining industries. Bottom Ash (BA), a coal industry by product, can serve as a reinforcement material in AMC. However, poor wettability during fabrication can weaken interfacial bonding and reduce mechanical performance. This issue can be mitigated by applying surface coatings to the reinforcement particles with the Electroless Coating (EC) method. This research investigates the utilization of Bottom Ash (BA) as reinforcement in Aluminum Matrix Composites (AMC) based on the Al-6061 alloy, with and without EC treatment. The process of making AMC was carried out using the stir casting method with variations of BA addition of 2%wt and 4%wt. Material characterization includes hardness testing, tensile strength testing, and metallographic observation. The results show that EC increases wettability, reduces porosity, and strengthens the interfacial bond. AMC with 2%wt bottom ash with electroless coating achieved a tensile strength of 122.6 MPa and a hardness of 45.7 BHN, significantly increased compared to without addition. At 4%wt bottom ash with electroless coating, the highest tensile strength of 128.2 MPa and hardness of 48.5 BHN were achieved, although without EC, the 4%wt fraction reduced strength due to agglomeration and the brittle intermetallic phase Al5FeSi. The EC treatment on bottom ash particles enhances their wettability and bonding with the Al-6061 matrix, leading to reduced porosity and minimized particle agglomeration.
